检索结果-南通市图书馆

Transport network and flow mechanism of shallow ore-bearing magma in Tongling ore cluster area

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China Earth sciences 2006年第4期49卷 397-407页

作者： DENG Jun1,2, WANG Qingfei1,2 , HUANG Dinghua3 , WAN Li4. YANG Liqiang1,2 & GAO Bangfei1,2 1. State Key Laboratory of Geological Processes and Mineral Resources, China university of Geosciences, Beijing 100083, China 2. Key Laboratory of Lithosphere Tectonics and Lithoprobing Technology of Ministry of Education, China university of Geo- sciences, Beijing 100083, China 3. Faculty of Earth sciences, China university of Geosciences, Wuhan 4.0074. China 4. school of mathematics and information science, guangzhou university, guangzhou 5104.5, China 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China 2. Key Laboratory of Lithosphere Tectonics and Lithoprobing Technology of Ministry of Education China University of Geosciences Beijing 100083 China 3. Faculty of Earth sciences China University of Geosciences Wuhan 430074 China 4. school of mathematics and information science Guangzhou University Guangzhou 510405 China

Abundant studies revealed that shallow intrusions of the Yanshanian epoch resulted in the mass mineralization of the Tongling region. Various evidences showed there existed a concealed magma chamber at ?10 km depth in the middle part of this region during Yanshanian epoch, from which the ore-forming magma was generated and then transported to the superficial layer. Yet the transport network and flow mechanism of the shallow ore-bearing magma, the key problem associ- ated with ore-forming process, was relatively little focused on. Integrate analysis of structural me- chanics, statistical fractal and geological facts suggested that NE trending high-angle fold-related thrust faults and the tessellated basement ones served as the main pathways for the shallow magma’s transporting, moreover, the saddle void spaces among adjacent strata in the folds upon this fault system provided the place for magma’s emplacement. So the folds in the upper part and faults in the lower part of the upper crust constituted the fluid’s transport and emplacement network. During the deformation of geologic body with multi-layer structure, the layers in the upper part tended to fold when received the jacking stress from the lower part, while the lower one inclined to fault undergoing loads of the upper part. And the producing probability of this structure assemblage was highly in- creased in the condition, such as in the Tongling area, that the mechanic rigidity of the lower layers was stronger than that of the upper ones. For the pre-existence of fluid-conducting network, the top magma with high volatile in the magma chamber transported rapidly to the superficial layer in dyking pattern, located in the void spaces of folds, filled and reconstructed them. The sudden drop of pres- sure caused the fluid unmixing from the magma and mass ore-forming elements concentration. Pulse activity of the dyking may be the principal reason why magmatic bodies in the Tongling area were spatially-temporally con

关键词： Tongling, structural network, magma intrusion, fractal, dyke.

Secure multi-party computation protocol for sequencing problem

在线全文

学校读者我要写书评

暂无评论

science China(information sciences) 2011年第8期54卷 1654-1662页

作者： TANG ChunMing 1,2,SHI GuiHua 1 & YAO ZhengAn 3 1 school of mathematics and information science,{4. university,{4. 510006, China 2State Key Laboratory of information Security, Institute of Software science,Chinese Academy of sciences,Beijing 100080,China 3 school of mathematics and Computational science,Sun Yat-Sen university,{4. 510275,China 1. school of mathematics and information science Guangzhou University Guangzhou 510006 China2. State Key Laboratory of Information Security Institute of Software Science Chinese Academy of Sciences Beijing 100080 China3. School of Mathematics and Computational Science Sun Yat-Sen University Guangzhou 510275 China

In the field of multi-party computation,an important problem is how to construct an efficient and secure multi-party computation protocol for certain specific *** the present study,we make use of a secret sharing scheme to construct an efficient and secure multi-party computation protocol for sequencing *** protocols are perfectly secure against both a passive adversary that can corrupt at most t (n-1)/2 participants, and an active adversary that can corrupt at most t < n/3 *** simplest sequencing problem is the Millionaires' problem.

关键词： secure multi-party computation sequencing problem secret sharing

On the diophantine equation X^2-(1+a^2)Y^4.=-2a

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China mathematics 2010年第8期53卷 2143-2158页

作者： YUAN PingZhi 1 & ZHANG ZhongFeng 2 1 school of mathematics,South China Normal university,guangzhou 510631,China 2 school of mathematics & Computational science,Sun Yat-Sen university,guangzhou 510275,China 1. school of mathematics South China Normal University Guangzhou 510631 China2. School of Mathematics & Computational Science Sun Yat-Sen University Guangzhou 510275 China

Let a≥1 be an *** this paper,we will prove the equation in the title has at most three positive integer solutions.

关键词： algebraic approximations continued fractions elliptic curves quartic equations

Perceptual video hashing robust against geometric distortions

在线全文

学校读者我要写书评

暂无评论

science China(information sciences) 2012年第7期55卷 1520-1527页

作者： XIANG ShiJun 1,4.,YANG JianQuan 2 & HUANG JiWu 3 1 school of information science and Technology,Jinan university,{4. 510632,China 2 Shenzhen Institutes of Advanced Technology,Chinese Academy of sciences,Shenzhen 518055,China 3 school of information science and Technology,Sun Yat-sen university,{4. 510275,China 4.State Key Laboratory of information Security,Institute of Software,Chinese Academy of sciences,Beijing 10004.,China 1. school of information science and Technology Jinan University Guangzhou 510632 China4. State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing 100049 China2. Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China3. School of Information Science and Technology Sun Yat-sen University Guangzhou 510275 China

In this paper,we propose a robust perceptual hashing algorithm by using video luminance histogram in *** underlying robustness principles are based on three main aspects:1) Since the histogram is independent of position of a pixel,the algorithm is resistant to geometric deformations; 2) the hash is extracted from the spatial Gaussian-filtering low-frequency component for those common video processing operations such as noise corruption,low-pass filtering,lossy compression,etc.; 3) a temporal Gaussian-filtering operation is designed so that the hash is resistant to temporal desynchronization operations,such as frame rate change and *** a result,the hash function is robust to common geometric distortions and video processing *** results show that the proposed hashing strategy can provide satisfactory robustness and uniqueness.

关键词： video hashing geometric distortion histogram Gaussian filtering

Optical pulse compression using a nonlinear optical loop mirror constructed from dispersion decreasing fiber

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(Technological sciences) 2004年第1期47卷 33-50页

作者： CAO Wenhua & LIU Songhaoschool of information, Wuyi university, Jiangmen 529020, China school for information and Optoelectronic science and Engineering, South China Normal university, guangzhou 510631, China 1. school of information Wuyi University 529020 Jiangmen China 2. school for information and Optoelectronic science and Engineering South China Normal University 510631 Guangzhou China

A novel scheme to compress optical pulses is proposed and demonstrated numerically, which is based on a nonlinear optical loop mirror constructed from dispersion decreasing fiber (DDF). We show that, in contrast to the conventional soliton-effect pulse compression in which compressed pulses are always accompanied by pedestals and frequency chirps owning to nonlinear effects, the proposed scheme can completely suppress pulse pedestals and frequency chirps. Unlike the adiabatic compression technique in which DDF length must increase exponentially with input pulsewidth, the proposed scheme does not require adiabatic condition and therefore can be used to compress long pulses by using reasonable fiber lengths. For input pulses with peak powers higher than a threshold value, the compressed pulses can propagate like fundamental solitons. Furthermore, the scheme is fairly insensitive to small variations in the loop length and is more robust to higher-order nonlinear effects and initial frequency chirps than the adiabatic compression technique.

关键词： dispersion decreasing fiber (DDF), optical pulse compression, optical solitons.

Periodic solutions of a 2nth-order nonlinear difference equation

在线全文

学校读者我要写书评

暂无评论

science China mathematics 2010年第1期53卷 41-50页

作者： ZHOU Zhan 1, YU JianShe 1 & CHEN YuMing 21 school of mathematics and information science,{4., guangzhou 510006, China 2 Department of mathematics, Wilfrid Laurier university, Waterloo N2L 3C5, Canada 1. school of mathematics and information science Guangzhou University Guangzhou 510006 China2. Department of Mathematics Wilfrid Laurier University Waterloo N2L 3C5 Canada

In this paper, a 2 nth-order nonlinear difference equation is *** the critical point theory, we establish various sets of sufficient conditions of the nonexistence and existence of periodic *** obtained complement or ... 详细信息

关键词： periodic solution nonlinear difference equation critical point theory

On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

在线全文

学校读者我要写书评

暂无评论

science in China(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2, 3 , FU Yuli 4.& XIE Shengli 4.1. Department of Control science & Control Engineering, Huazhong university of science & Technology, Wuhan 4.0074. China 2. school of Automation, Wuhan university of science & Technology, Wuhan 4.0070, China 3. school of information, Central South university of Economy, Politics and Law, Wuhan 4.0064. China 4. school of Electronics & information Engineering, South China university of Technology, guangzhou 51064., China Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) 1. Department of Control science & Control Engineering Huazhong University of Science & Technology 430074 Wuhan China 2. school of Automation Wuhan University of Science & Technology 430070 Wuhan China 3. school of information Central South University of Economy Politics and Law 430064 Wuhan China 4. school of Electronics & information Engineering South China University of Technology 510640 Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

A note for preconditioning nonsymmetric matrices

在线全文

学校读者我要写书评

暂无评论

Applied mathematics(A Journal of Chinese Universities) 2010年第1期25卷 93-100页

作者： CHEN Xiao-shan LI Wen school of mathematics, South China Normal university, guangzhou 510631, China school of mathematics South China Normal University Guangzhou China

In this paper, we consider preconditioners for generalized saddle point systems with a nonsymmetric coefficient matrix. A constraint preconditioner for this systems is constructed, and some spectral properties of the ... 详细信息

关键词： Preconditioner saddle point matrix minimal polynomial Schilder's factorization.

Accurate determination of the plate model based on CCD images with different orientations

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 2010年第9期55卷 791-796页

作者： PENG QingYu1,2,3,4.& FAN LiangYan1,2,3,4.1 Joint Laboratory for Astrometry, Dynamics and Space science, Jinan university, guangzhou 510632, China 2 Department of Computer science, Jinan university, guangzhou 510632, China 3 Key Laboratory of Optoelectronic information and Sensing Technologies of Guangdong Higher Educational Institutes, Jinan university, guangzhou 510632, China 4.Joint Laboratory for Optical Astronomy, Chinese Academy of sciences, Kunming 650011, China Joint Laboratory for Astrometry Dynamics and Space Science Jinan University Guangzhou China Department of Computer science Jinan University Guangzhou China Key Laboratory of Optoelectronic information and Sensing Technologies of Guangdong Higher Educational Institutes Jinan University Guangzhou China Joint Laboratory for Optical Astronomy Chinese Academy of Sciences Kunming China

The images of the open cluster NGC2168 are taken using the newly-fitted 2k×2k CCD attached to the 1-m telescope at the Yun-nan Observatory with two different orientations. After the catalogue position of a star from UCAC2 is compared with its corresponding measured position, a surprising result shows that a small field of view (about 7′×7′) exhibits an obvious distortion. Spe-cifically, the polynomial between the standard coordinate (ξ,η) and its corresponding measured one (x,y) for a star in each field of view has significant terms as high as 4.h order. Accordingly, the positional measurement accuracy of a bright UCAC2 star can be derived as well as ~7 mas in each direction (60 s of exposure time and near the zenith). This new finding would be important for a CCD image to deliver a highly accurate position in its whole field of view.

关键词： CCD imaging field distortion positional measurement image analysis